Collimatrix

It's not that crazy:
 
-YF-17 was a Northrop bird.  Ostensibly it was their entry into the LWF competition, but actually they'd been working on an F-5 replacement for years before the competition was announced.  This used YJ101 "leaky turbojet" engines.  This lost to the YF-16 for the LWF bid, but some genius had meanwhile decided that the Navy would have to buy LWFs as well, not realizing that carrier birds are much, much better off if purpose-designed.
 
-F/A-18 was the ultimate result of this foolishness.  Although the YF-16 was the better design in most respects, the YF-17 was drastically better suited to carrier operations thanks to twin engines, much wider landing gear and lower landing speeds and AOA.  However, Northrop had no experience making carrier birds, so they partnered with McDonnell Douglas, who had the entire phantom/banshee/demon/phantom II family of carrier fighters under their belt.
 
The changes from YF-17 to F/A-18 were quite major.  F/A-18 was going to be a multi-role aircraft, not just a simple day fighter.  to that end a whole mess of new avionics were added, chiefly a much bigger and better radar and also the most advanced cockpit of the time, were added to the aircraft.  Because the aircraft would be tasked as a fighter and as an attack aircraft, a lot of work went into designing cockpit instruments that could display lots of information in a smooth, efficient way.  
 
The structure was reinforced to withstand carrier operation and anti-corrosion coatings were added where needed to survive being next to the ocean all the time.  The engines were now the godly GE F404; hands down the best fighter engine until the F110.  Weight went up enormously (about 30%) and the wings were enlarged to compensate.  To try and minimize weight increase, a large percentage of composites were used to replace traditional aluminum structure.  Initially, F-15 style dogtooth leading edge vortex generators were added to the wings and horizontal stabilizers, but these were later deleted.  The gap between the LERX and the fuselage was also eliminated, except for a small slot for boundary layer air from the inlets.
 
F/A-18L:  McDonnell Douglas and Northrop agreed to share production responsibilities on the F/A-18, with some parts coming from each company.  In the meantime, however, Northrop was given full responsibility and ownership of the F/A-18L design, which would be a de-navalized F/A-18.  The advanced avionics, new engines and aerodynamic refinements would stay, but the structure would be made lighter and some of the special corrosion-resistant materials would be removed in order to save weight.  The aircraft was never built; Northrop simply dressing up the YF-17 prototypes to play the part.  Canada and a few other countries seriously flirted with the idea of buying these, but in the end all prospective buyers either bought regular F/A-18s or F-16s.
 
-F/A-18E/F:  In 1987, McDonnell Douglas submitted a series of proposals for developments of the F/A-18 under the name "Hornet 2000."  Configuration 1 was a fairly simple upgrade with uprated engines, a more powerful radar, and some updates to the avionics and cockpit.  Configuration 2 was similar, but further featured some structural improvements to the wings, and an extended fuselage spine to house extra fuel.  Configuration 3 took configuration 2 and added a larger wing and tail and even more fuel.  Configuration 4 was a new aircraft altogether; a canard-configured hornet intended to lure away members of the then-troubled Eurofighter program.
 

 
None of these proposals ever proceeded, but the spectacular failure of the USN's A-12 program did create a need for some sort of stopgap until the NATF arrived (NATF also failed).  The superhornet was thus created.  Shornet is similar to configuration 3 of the hornet 2000 proposal, but with some further elaborations.  The engines are the new F414, which is based on the F404, but incorporating changes intended for the engines of the A-12 as well as changes made by the Swedes for the gripen.  The latest version of the F414 produces over double the thrust of the YJ101; the engine that the core was originally based on.  The radar is new, additional weapon stations have been added, the LERX have been redesigned to clear up some nagging issues with the vertical stabilizer interacting with the vortices, and the inlets have been redesigned to accommodate the new engines as well as to reduce radar cross section.
 
Since the super hornet is literally the only fixed wing carrier-based aircraft to be designed since the 1970s, it's been forced to do all sorts of other things like tanking and EW.  Thus, the buddy tanking system and the EA-18 Growler.
 
In the meantime, McDonnell Douglass merged with Boeing, which is why the shornet is a Boeing bird now.

Their overall design rationale reminds me a lot of the conceptual studies in British tank guns that led up to the 120mm L11.  Lower breech pressure means that the breech, ceteris paribus can be narrower and thus take up less room in the turret because the breech ring and barrel don't need to be as thick.  This also makes stabilization a little easier because there's less steel for the stabilizer to have to wrestle with.  Lower peak pressure also makes life a little easier for the ammunition designers because the interface between the sabot and the dart is experiencing less peak force.

The problem with this line of thinking is that it's really hard to get the raw performance.  Kinetic energy of the projectile is the integral of the pressure at the base of the projectile swept along the volume of the bore.  For a given mass of propellant, higher pressure guns have better thermodynamic utilization of the propellant.  In small arms, higher peak pressure also gives more consistent internal ballistics and thus accuracy, but I am not sure if this is a major factor in tank guns.

The Rheinmetall 130mm has the same cartridge base dimensions as the 120mm:



So the increase in breech thrust against the breech block and the stress in the firing chamber and breech ring should only be greater by (approximately) the percentage increase in pressure.  On top of that, the breech designs Rheinmetall has shown have a more sophisticated wedge design that existing 120mm guns which should provide better distribution of the firing loads and thus lower peak stress:



There may also have been metallurgical improvements in gun breech materials in the... what, half century since the 120mm smoothbore was invented?

So the width increase of the 130mm vs. the 120mm may be very small.  The gun will probably need greater recoil travel and may need to be mounted further back in the turret, so it is not space-neutral or anything like that.  However, with the current manned tank turret design of placing the gunner, gun, and commander abreast (or loader, gun and gunner in designs with a flesh loader), the width of the gun breech is dividing the turret right down the center and determines to a large degree how much elbow room is left for the crew for a given turret ring diameter.

So, given that the Rheinmetall design is more mature, more powerful, and shouldn't be too much wider than the existing 120mm smoothbore, the advantages the Ascalon offers seem poor by comparison.

The interface between the sliding wedge of the breech block and the breech ring is what is improved.



As you can see, on the M256 the shoulder in the breech ring that the sliding wedge rests against is a single element that's more or less a square corner (albeit radiused).  In the Rheinmetall 130mm weapon you can see that the interface between the sliding wedge and the breech ring has two layers, and that it's sort of a rolling teardrop shape with a much more generous radius.  It's not unlike what the US was looking at with the XM360:



It's been known for a very long time that this sort of design of sliding wedge is stronger, but it's traditionally been considered too much of a pain in the ass to manufacture to be worth it.  Perhaps computer stress modelling and improved manufacturing technology have changed that.

By reducing stress I mean it reduces stress in the metal of the breech mechanism.  The stress at any given point in the breech ring and the breech block has to be lower than the yield strength of whatever uber-steel it's made out of so the gun isn't permanently deforming itself with each shot.  Ideally the stress should be quite a bit lower in order that the mechanism has good fatigue life.  When the original 120mm Smoothbore was designed (late 70s) I doubt that full computational finite element analysis was possible; the computers were too pathetically weak back then.  The stress analysis was probably done with some computer modelling, but also good old fashioned rules of thumb and photoelastic stress simulations:



It is possible to modulate pressure within the tube with propellant design, but to what end?  Yes, pressure in the breech is what causes the stress on the locking elements.  Pressure in the breech is also what makes the projectile go downrange.

Keeping the peak recoil force within reasonable bounds is important as well, so I suspect that the recoil system on the 130mm will need to permit the gun to travel further than the system in current 120mm armed vehicles.  However, increasing the travel of the gun during recoil doesn't really change the width of the gun system that much.  Look at how cramped the gunner's position is in an Abrams, which is supposed to be one of the MBTs with more generous elbow room:



That position, by all accounts, kind of sucks, but if the gun gets even a few centimeters wider it's going to suck way more.

No.  The stabilizing lift force provided by the fins is a function of angle of attack times fin area times airspeed squared.  The overturning moment acting on the rod is a function of the moment arm between the aero center and center of gravity times airspeed squared.  The stabilizing moment provided by the fins is a function of their stabilizing lift force times the moment arm between the fins and the center of gravity.  Thus, as long rods have gotten longer and longer, these competing effects have more or less canceled out and the fins have stayed about the same size.
 


Because the stabilizing force provided by the fins is a function of airspeed squared and the overturning force is also a function of airspeed squared, a long rod penetrator that's stable at one airspeed is stable at any airspeed.  The only exception is the transonic where lift coefficients and aero centers can jump around, but that's pretty much academic because an APFSDS long rod going transonic velocities isn't going to be killing very much.
 

Their overall design rationale reminds me a lot of the conceptual studies in British tank guns that led up to the 120mm L11.  Lower breech pressure means that the breech, ceteris paribus can be narrower and thus take up less room in the turret because the breech ring and barrel don't need to be as thick.  This also makes stabilization a little easier because there's less steel for the stabilizer to have to wrestle with.  Lower peak pressure also makes life a little easier for the ammunition designers because the interface between the sabot and the dart is experiencing less peak force.

The problem with this line of thinking is that it's really hard to get the raw performance.  Kinetic energy of the projectile is the integral of the pressure at the base of the projectile swept along the volume of the bore.  For a given mass of propellant, higher pressure guns have better thermodynamic utilization of the propellant.  In small arms, higher peak pressure also gives more consistent internal ballistics and thus accuracy, but I am not sure if this is a major factor in tank guns.

The Rheinmetall 130mm has the same cartridge base dimensions as the 120mm:



So the increase in breech thrust against the breech block and the stress in the firing chamber and breech ring should only be greater by (approximately) the percentage increase in pressure.  On top of that, the breech designs Rheinmetall has shown have a more sophisticated wedge design that existing 120mm guns which should provide better distribution of the firing loads and thus lower peak stress:



There may also have been metallurgical improvements in gun breech materials in the... what, half century since the 120mm smoothbore was invented?

So the width increase of the 130mm vs. the 120mm may be very small.  The gun will probably need greater recoil travel and may need to be mounted further back in the turret, so it is not space-neutral or anything like that.  However, with the current manned tank turret design of placing the gunner, gun, and commander abreast (or loader, gun and gunner in designs with a flesh loader), the width of the gun breech is dividing the turret right down the center and determines to a large degree how much elbow room is left for the crew for a given turret ring diameter.

So, given that the Rheinmetall design is more mature, more powerful, and shouldn't be too much wider than the existing 120mm smoothbore, the advantages the Ascalon offers seem poor by comparison.

There was an interesting thread by Ronkainen on Twitter that looked into the support capabilities (trailers, bridging, recovery etc.) that US Army Infantry Divisions would need to operate the two MPF candidates, but unfortunately I can’t seem to dig it up because I don’t have (never had) a Twitter profile. Anyway, the gist of it was that the equipment required to support BAE’s candidate already existed in these divisions (if not in the quantities necessary), while for GD’s candidate it would have to be beefed up substantially, and to a point where it started to resemble that of an Abrams unit.
 
Edit: I finally found it
 
 

Their overall design rationale reminds me a lot of the conceptual studies in British tank guns that led up to the 120mm L11.  Lower breech pressure means that the breech, ceteris paribus can be narrower and thus take up less room in the turret because the breech ring and barrel don't need to be as thick.  This also makes stabilization a little easier because there's less steel for the stabilizer to have to wrestle with.  Lower peak pressure also makes life a little easier for the ammunition designers because the interface between the sabot and the dart is experiencing less peak force.

The problem with this line of thinking is that it's really hard to get the raw performance.  Kinetic energy of the projectile is the integral of the pressure at the base of the projectile swept along the volume of the bore.  For a given mass of propellant, higher pressure guns have better thermodynamic utilization of the propellant.  In small arms, higher peak pressure also gives more consistent internal ballistics and thus accuracy, but I am not sure if this is a major factor in tank guns.

The Rheinmetall 130mm has the same cartridge base dimensions as the 120mm:



So the increase in breech thrust against the breech block and the stress in the firing chamber and breech ring should only be greater by (approximately) the percentage increase in pressure.  On top of that, the breech designs Rheinmetall has shown have a more sophisticated wedge design that existing 120mm guns which should provide better distribution of the firing loads and thus lower peak stress:



There may also have been metallurgical improvements in gun breech materials in the... what, half century since the 120mm smoothbore was invented?

So the width increase of the 130mm vs. the 120mm may be very small.  The gun will probably need greater recoil travel and may need to be mounted further back in the turret, so it is not space-neutral or anything like that.  However, with the current manned tank turret design of placing the gunner, gun, and commander abreast (or loader, gun and gunner in designs with a flesh loader), the width of the gun breech is dividing the turret right down the center and determines to a large degree how much elbow room is left for the crew for a given turret ring diameter.

So, given that the Rheinmetall design is more mature, more powerful, and shouldn't be too much wider than the existing 120mm smoothbore, the advantages the Ascalon offers seem poor by comparison.

No.  The stabilizing lift force provided by the fins is a function of angle of attack times fin area times airspeed squared.  The overturning moment acting on the rod is a function of the moment arm between the aero center and center of gravity times airspeed squared.  The stabilizing moment provided by the fins is a function of their stabilizing lift force times the moment arm between the fins and the center of gravity.  Thus, as long rods have gotten longer and longer, these competing effects have more or less canceled out and the fins have stayed about the same size.
 


Because the stabilizing force provided by the fins is a function of airspeed squared and the overturning force is also a function of airspeed squared, a long rod penetrator that's stable at one airspeed is stable at any airspeed.  The only exception is the transonic where lift coefficients and aero centers can jump around, but that's pretty much academic because an APFSDS long rod going transonic velocities isn't going to be killing very much.
 

No.  The stabilizing lift force provided by the fins is a function of angle of attack times fin area times airspeed squared.  The overturning moment acting on the rod is a function of the moment arm between the aero center and center of gravity times airspeed squared.  The stabilizing moment provided by the fins is a function of their stabilizing lift force times the moment arm between the fins and the center of gravity.  Thus, as long rods have gotten longer and longer, these competing effects have more or less canceled out and the fins have stayed about the same size.
 


Because the stabilizing force provided by the fins is a function of airspeed squared and the overturning force is also a function of airspeed squared, a long rod penetrator that's stable at one airspeed is stable at any airspeed.  The only exception is the transonic where lift coefficients and aero centers can jump around, but that's pretty much academic because an APFSDS long rod going transonic velocities isn't going to be killing very much.
 

Nexter's Ascalon concept undergoing live fire trials at Alcochete (Portugal) :
 
Sadly, no public images available yet.
Ascalon is a 140 mm gun using telescoped ammunition (meaning potentially longer APFSDS rods and more ammunitions onboard) and is the main competitor of Rheinmetal's 130 mm for the MGCS.
 
The energy at the muzzle, is not overly impressive at 10MJ (with a goal of 13MJ by 2025) compared to the 9-12MJ of current 120mm but Nexter claim to reach those energy at a lower chamber pressure than current guns.
 
So we have two concepts going in opposite directions. Rheinmetal's 130mm will have a much higher muzzle energy than the current generation of guns (50% more according to Rheinmetal) which mean that the platform using it will have to be sturdy enough to withstand the recoil, while Nexter is going toward a lower energy gun (compensated by longer kinetic penetrators) which could theoretically be mounted on lighter platforms. That might show opposite visions for the MGCS which lines up somewhat with the operational culture of both country. A heavier tank geared more toward territorial defense for Germany, and a lighter more deployable platform for France.
 
The 130 mm is also using mature and proven technological solutions, while a 140 mm CTA is (as far as I know) something new which may lead to hurdles during the development process. So the maturity of the technology (which will be somewhat linked to the cost) will also be a factor.

The RARDE 110 mm (Short) gun, also known as the EXP-7 fired its APDS at a muzzle velocity of 1387 m/s with a velocity drop of 62 m/s at 1000 m.
At this range it was able to penetrate a 152 mm armor plate sloped at 60° and thus the NATO heavy single target.
 
For comparison, the L15A3 APDS fired from the larger L11 120 mm tank gun of the Chieftain main battle tank had a muzzle velocity of 1370 m/s with a velocity drop of 60 m/s at 914 m and was able to penetrate, at this range a 150 mm armor plate at 60° (likely the NATO heavy single target).
 
In spite of its slightly smaller calibre, the EXP-7 could penetrate as much, if not more, armor than the 120 mm L11 tank gun.

Wanted to do this post 2 days ago after digesting new events, but was too exhausted after workshifts to do effortposting, i was coming back to home during night time. My thoughts on this war, noise surrounding it, strategical implications and expectations, for those who care.
 
 
What i think.
   After 2017 it was obvious Ukraine will not do anything from Minsk agreements as Ukr politicians were publicly shitting on them and were doing nothing to make it real. DPR and LPR fate became obvious - they are not wanted in Ukraine. Putin's decision to recognize republics was constatations of situation. I expected thing to go slowly but deliberatly towards something i will describe later. But events went in very different way from what i thought would happen. Now, i'm not going to spit in the back of our soldiers executing orders, as Army should be this way, but politicians and other higher ups are free game im my eyes.
 
   Decision to start a full scale war in my opinion was stupidiest thing our political leadership have done in past 22 years. I'm not sure why or what triggered it, but looks like a plan was being worked on for long time, probably even before last year. Putin usually was carefull, but this is rackless decision.
   Our PR can scream about this operation being against nazis and nationalists, but the fact is this war is against Ukraine and everyone inside of it, as effects of war are going to touch nearly everyone who lives inside directly or indirectly.
 
   I don't have hard feelings about it, as i "burned down" during 2015, but this was wrong call. Not because war is bad, but because net result is not going to be what i would like to see.
 
 
   Good vs Evil
   Now, in medias narrative is that Good Democratical Ukraine is fighting Evil Russian dictatorship, in my view both states are dogshit.
 
   Ukraine is highly corrupted country that was run by oligarchs before coup in 2014 and now sort of run by oligarchs together by nationalists with piece of sovereignty outsorced to US foreigh policy makers, a country that effectively suppressed opposition in 2015-16 and where you have less rights than even in Russia, if you are not following "main course". One time per few years population needs to go to specific places where they instal another politicain as a leader who will became highly unpopular by the end of his term.
 
   Russia is highly corrupted country that was run by oligarchs before Putin and now sort of run by oligarchs together with Putin and his "clan", a country that sort of suppressed opposition in 2000s and where you have some rights, but there are workarounds, if you really want to. One time per few years population needs to go to specific places where we approve prolongation of power of our leader.
 
   Personally, i fail to see who is here an actual good guy. Both, in grand scheme of things, are kind of assholes. Maybe reason for people far away to see this conflict differently than war between Azerbaijan and Armenia is mix of agressor vs defender and Goliath vs David situation, and the fact that what they see on videos is a country and people more relatable than some Middle Eastern Arabs that are getting democracy delivered to their homes. But that is how i see it.
 
 
   Why this war is in such way it is (copy pasted from Discord): 
 
   I think we started this war with soft boxing gloves on, for some fucking reason. Maybe they expected less resistance, which may show how much attention they gave to situation on Donbass and how well they took into account 8 years of nationalistic propaganda and having armed conflict in 2.5 regions.
 
   Note absolutely no videos coming from our MoD, nothing about combat. Also note how for several days we used no artillery, very limited cruise missile strikes and no airstrikes (like in Syria with 100+ sorties per day from small base in Hmeimym). All this led to major units not being destroyed, equipment partially left in working condition. Internet was not turned off, mobile phones working. They did jack shit on this front. They did half measures and got half results.
 
   Thanks to that UAF was not destroyed. Convoy routes left undefended. No use of CAS, no proper AA coverage. Big units in bypassed cities left without serious blocking formations. They can orginise by using just mobiles phones. Thanks to ability to film and upload videos to the internet, net is now flooded with videos of Russian equipment destroyed and soldiers killed. Uplifting material for other side. All this instead of getting moral collapse of enemy faster and destruction and murder to minimun turned 180. Ukrainians are fighting back harder that what was anticipated is my expectation.
 
   Another boggus decision was using such small number of forces for operation. I saw claims of ~50k in initial phase. 100k is possibly going to be total number of forces. Ukraine is 40+ mln country. Not sure how they will hold it. Even with Rosgvardia there is not enough people to hold whole country.
 
   In the end results will be same on grand scale, but path to that result will be bloodier and longer. I guess thats why Putin fired that big star commander. But i guess they had plan B for bloodier route, which is why we now see MRLS used to bombard enemy.
 
   You can't "half-fight" the war, trying to look friendly on tv. What was supposed to be public flogging of Ukraine starts to be 1939 Soviet war with Finland, where USSR technically won, but Germans, looking at how it was won, thought Red Army was umm.. "incompetent" and decision to invade USSR was taken with taking into account poor results of that war. 
 
 
   Expectations, future
   After declaration of recognition of republics i thought we will start to help rebels in taking back 2 oblast', and this will be the end of hot-ish phase of conflict in Donbass region after quick strike against main forces of UAF in this region (which are most of their forces) and enforcing some sort of political comma in a conflict and moving to next phase.
 
   Reality went in different direction.
   I suspect this war will continue for a week (optimistically), 2-3 weeks if Russian command will not unfuck their plans, or turn into strange military stalment for a month or 2 when most of Ukraine is going to be technically captured, but vast territories and many towns/villages will not have any occupation forces to keep an order, so motivated people will have space to continue strategically unorginised conflict until we will pump necessary amount of internal troops to put it down enough for law enforcements to handle situation.  
 
   After that expect new government, neutral status and Russian troops leaving, with scars of stupidity of leadership. And after some time - nationalists will rise, again, maybe even at bigger scale. Reason - they were screaming about Russian invasion for 8 years and now it is a reality. Their voice was heard by people in Ukraine before, but and now it have big and firm foundation to stand on thanks to this war happening.
 

BVMs in Belarus. Possibly will be spotted during fighting in Ukraine
 

More Hanwha Redback promo/propaganda 
 
 

Photos of K1E1s, K1 ARV, and K200s of the 20th Armored Brigade during a recent cold weather training exercise


 

Ian got his hands on NK LMG
 

https://yuripasholok.livejournal.com/13716017.html
Yuri Pasholok's photos of Object 781 variant B. According to placard it had crew of 7 (!).

   Turret weapons same as on BMP-3 (100 mm 2A70 gun-launcher + 30 mm 2A72 AC+ PKT) + 30 mm Balkan AGL + PKT in RCWS. Add here AGL in hull + 2 MG gunners on hull sides, vehicle was capable of firing at 6 directions in the same time.
   Hull is modded T-72 chassis.
 
 

 
 

 
 

And something unusual.
 
DP-61 Duel' 55 mm caliber grenade launcher.
https://war-time.ru/item/dp-61-duel

 
   Was designed in end of 1970s for Soviet Navy to defend ships and coastal structures against attacks by frogman. 2 man crew, loaded from rear, max range is 1 km, aimed fire - up to 500m, weight - 6 kg. Elevation of tube instead of the sights to account for ballistics at given range is visually noticeable feature of this RPG weapon.
 

   RG-55M rocket propelled grenade is used. It have contact fuze for surface targets and delayed fuze if gunner tries to engage enemies underwater. Delayed fuze is set by a special key that lets crew select a depth of detonation. Kill radius is about 18 meters. 3 types of grenades are avaliable - contact/depth detonation grenade, signal, training round.
 

 
 
 
Of course, a bit better known 2 tube version of DP-61 Duel - DP-64 Nepryadva grenade launcher. 

   Unlike DP-61, DP-64 isn't mass produced for our Navy, although was adopted for service and also DP-64 is a grenade launcher, while DP-51 is basically an RPG launcher like RPG-7. 
 

 
10Kg, max range is 400 meters, loaded from through rear breach with 45 mm caliber FG-45 grenades. Grenades have depth fuze like on RG-55Ms on DP-61, can be set up to 40 meters depth detonation with kill radius of about 14 meters
 
 

The US State Department and other US government organs believed their own propaganda.  Remember this?



The US government is filled with aging Baby Boomers who feel considerable nostalgia about the social uprisings that defined their generation.  They also feel guilt about not having participated in them more vigorously, and wish to vicariously participate in such uprisings elsewhere.  They became convinced that the entire Arab world was filled with hip, Western-educated young people who aspired to live in shiny, Western-style democracies instead of shabby, corrupt dictatorships.  With a little help from their friends in Washington DC, they could make their dreams a reality!  Yes we can!
 
Also, once the revolution was complete there were going to be some shady oil deals and whatnot to sweeten the deal for some of the people involved.  The first batch of diplomatic cable leaks have alluded to some of these.  But this isn't to say that the US government started all this chaos to get their hands on oil.  They're simply not that rational.  The horrifying thing about US foreign policy is that the US is so overwhelmingly powerful, and so completely insulated from the consequences of its actions, that the primary goal of US foreign policy is to posture and to gain advantage in US domestic politics.  If you live outside the US, you are just a puppet on a string, dancing to a solipsistic and insane tune played by the blind idiot god of America.  Unless you live in Russia or China and to a lesser extent India.  They have nukes and they're not afraid to tell the US government to shove it.  Everywhere else?


 
So, the Democratic Party and their extended network of allies in the State Department and elsewhere decided to prove their purity and support for Democracy by assisting in the overthrow of secular dictatorships throughout the Middle East.  This was, in retrospect, and also a the time, obviously a bad idea.  While these countries did have large numbers of hip, westernized youth who were tired of the corruption and economic stagnation of their homelands, these countries had even larger numbers of Islamists who were older, better-funded, better-organized, and far better at playing the game.  The results were entirely predictable; the young, cool, hip protesters who basically wanted to turn the entire southern coast of the Mediterranean into LA were quickly displaced and cowed into silence by barbarians who want to dynamite the pyramids and conquer all of their neighbors so they can have them as rape-slaves.  Also, I want to point out that that last sentence sounds like a breezy, poetic exaggeration but it's actually literally true.
 
This happened pretty quickly; it was obvious that Islamist elements were wearing the pants only a few months into the Arab Spring movement.  But the US government does not let mere facts stop it.  Instead of quickly pulling support and walking away while pretending nothing happened at all, the US government decided that if Islamists had taken over pro-Democracy protests, Islamists must be the true face of Democracy in the Middle East.  Seriously; that's how come you get retarded buzzfeed articles like this one lamenting the suppression of the Muslim Brotherhood.
 
Very quickly, a number of governments that managed not to implode decided that if Uncle Sam was going to act all retarded and shit, they might as well do their best to make sure that it was directed at their enemies.  These countries, chiefly Saudi Arabia, Qatar, Turkey and Israel, formed a surprisingly effective alliance of strange bedfellows that aimed at exporting their domestic political problems and at sticking it to the Persians.  Saudi Arabia has a long history of religious radicalism, and an almost equally long history of exporting those radicals so they can get killed by airstrikes from civilized countries.  Qatar is a Salafist country that is looking very nervously at their own 20% Shia minority and what's going on in Yemen and Iraq.  Turkey is run by a knuckle-dragger who stays on top because his opponents are completely retarded, and who needs displays of foreign military might to keep his base satisfied with his lack of internal success.  Israel's Likud government has a precarious hold on power and opposes an Iranian ally and long-standing rival.
 
So, by making sure that a bit of money got into the right pockets, this coalition has kept the mostly Islamist opposition in Syria fed and armed.  Propaganda in the US, funded by the Saudis and powered by boomer egos, has mainly kept the public from realizing that this is exactly the sort of anthill that the US does not need to stick its dick into, although they have remained opposed to large-scale deployment of ground forces.
 
The biggest losers are, of course, the mainly secular, hip, westernized youth for whose benefit this idiotic operation was started.  And yes, I'm sure they would grit their teeth and side with Assad if any of them haven't been killed.

some thoughts on 477A based on available info 

As for what a 1990s tank would realistically look like, by the 1990s most tanks were really samey.
 
Powerplant:  The earliest tanks with diesels were experimented with in the 1930s, I believe either the Japanese or the Soviets were the first.  By the 1940s the advantages were obvious, but de-rated aviation gasoline engines were reliable and already in mass production, so many countries stuck with those.  I'm less clear on the rationale for the Germans keeping gasoline motors as theirs were not aeroderivative.  In any case, there actually was a German tank diesel program, it just went nowhere.

By the 1990s there were pretty much two realistic possibilities for a tank powerplant; either a turbodiesel or a gas turbine.  1990s MBTs are about half armor by weight, so they're very sensitive to the compactness of things.  Turbocharged diesels don't have amazing power density, although with a lot of careful engineering they can be made competitive, but they have very low fuel consumption and lower waste heat rejection requirements than gasoline engines.  Once you factor in the volume of the engine plus the volume of the fuel plus the volume of the cooling fans, and the strategic mobility advantage the fuel-sipping diesel, it's definitely coming out ahead of the gasoline motor.

Gas turbines do not scale down particularly well.  Very large gas turbines like the 33,000 horsepower Rolls Royce WR-21 naval gas turbine in the Type 45 destroyer achieve 42% thermal efficiency, which is like middling efficiency by diesel standards.  A gas turbine that will fit inside of a tank is much less efficient; realistically about a match for a gasoline engine in terms of specific fuel consumption when it's at design point and much worse if it's idling or doing any kind of stop and go.  Gas turbines also need beefier air filters than diesels due to much higher mass airflow through the engine.  However, there are still a number of advantages that must be taken into consideration.  Gas turbines are (very nearly) completely self-cooling, so while there will still need to be cooling fans to keep the transmission cool, the total powerpack losses to cooling power will be smaller and the ballistic windows from the ventilation will be much smaller.  Gas turbines with a free power turbine (which is most of them) have a very different torque/RPM characteristics from a diesel; they produce max torque at their lowest RPM and max power at their minimum torque.  These are very favorable characteristics if you want to keep the transmission small (although the Abrams' XR-1100 transmission was, as I understand, designed to work with both the AVCR-1360 and AGT-1500 so it likely does not take much advantage of this effect).  Gas turbines are easier to start in the cold.  Gas turbines have very little vibration because their moving parts rotate rather than reciprocate.  Gas turbines are actually multi-fuel, no questions asked and no mucking around with adjusting the engine to suit the fuel.  The Brayton cycle uses continuous, constant-pressure ignition which simply does not care about octane numbers or cetane numbers.  Finally, it's easier to design gas turbine fuel burners so they produce very little smoke than it is to ensure that a diesel produces very little smoke due to the much different fuel burn stoichiometry of a gas turbine.  It should be noted that not all gas turbine designers have actually succeeded in doing so, however.

A gas turbine good enough for a tank would be roughly similar to a turboshaft for a helicopter, albeit tweaked more for better fuel consumption than for absolute power to weight ratio.  The list of countries that can design very good turboshaft engines is quite short, but then so is the list of countries that can make high specific power diesels.  If tank-sized gas turbines performed as well as ship-sized ones this would be no contest, but they don't so either choice is competitive and it's pretty ambiguous which is "best".  But most countries in the world realistically do not have the luxury to pick and choose between a top of the line diesel and a top of the line turbine.  Interestingly, the UK is in a position to make such a choice and they still managed to fuck it up somehow by fielding a tank diesel that's 300 horsepower short of its stablemates.  The French hyperbar engine is a turbocharged diesel, just tweaked for very fast throttle response and compactness at some expense to efficiency.

Armament:  By the 1990s, advances in digital fire control systems largely rendered gun-launched missiles obsolete.  There was probably still a case for them as a sort of long-range precision round for swatting at helicopters and the like, but that role could also be filled with something like M830A1.  There were various flirtations in the mid Cold War era with sorta-kinda howitzer like armament for tanks in the form of medium pressure guns and gun/launcher hybrids, but by the late 1970s there was basically a consensus amongst all sensible people that the tank armament of the future would either be the Rheinmetall 120mm or would look a lot like it.  Even British engineers were aware of this:



In any event, the Soviets taking their toys and going home meant that the world did not suddenly fill with various super-tanks, and tank lethality ended up being more economically improved by advances in ammunition design rather than arming the tanks with larger guns.



You can't go too much larger than current 120mm without requiring an autoloader.

As LoooSeR said, context is important.

During the 1940s, tanks were simple enough that relatively small countries could design and field reasonably competitive designs on their own.  The expertise required for tanks largely overlapped with either other armament industries (tank guns were often adapted naval, AA guns, or field artillery and the engines were often modified aircraft powerplants), or civilian heavy industries (much of the casting/welding and transmission design could be readily adapted from car/train/ship making industries).

By the 1990s, however, tanks were much higher tech and a lot of that tech was much more tank-specific.  It should be possible to adapt a helicopter turbine or heavy prime mover engine to work in a tank.  Fabrication of the hull could still probably be done with expertise from other industries.  Production of the special armor packages, transmission and running gear would require tank-specific knowledge but not necessarily tank-specific industry.  Production of the gun, fire control systems, and other combat electronics would by that point require very specific knowledge and would overlap relatively little with too many other things already in production if it were a nation's first tank.

I think it's instructive to look at the smallest/poorest countries that have produced their own tanks.  Romania was able to produce the TR-85, albeit in somewhat limited quantities, and they didn't design their own gun, and the turret and hull design are at least based on the design of the T-54/55 albeit very heavily modified.  As far as I can tell they did design their own engine and transmission, which is quite impressive, but this took some time and all the while they were cribbing notes off of foreign designs.  No shame in that; high specific output diesels are not easy to design.

Israel designed the Merkava, which has a completely original hull and turret design, locally designed suspension and tracks, and locally designed special armor packages and fire control on the later models.  The engine is either US or German designed, and the transmissions have been US, German or Israeli designed based on the mark.  The gun was a straightforward clone of the M68, and later a locally designed version of the German 120mm smoothbore.  Both of these guns are compatible with the wide range of ammunition in either caliber, although Israel has a local ammunition industry capable of designing and producing its own tank gun ammunition (which in some cases has been widely adopted outside of Israel).

South Korea has produced two MBTs locally, the K1 and K2.  The former had a great deal of assistance from Chrysler, but the latter appears to be a largely local effort.  Early K2s had a German designed engine and transmission, but these are eventually to be phased out and replaced with locally-designed equivalents.  I believe the tracks are German-designed.  Not sure about the suspension.  The armor packages and fire control system are locally designed and manufactured.  The gun is some sort of version of the German 120mm, although again South Korea is capable of designing and producing their own ammunition.

Turkey, which has roughly the same size economy as South Korea if we discount their current economic woes, has had a much harder time developing their own MBT.  Despite considerable help from South Korea, they have struggled to develop their own engine and transmission and are currently dependent on political good will from Germany if the project is to go forward quickly.  I don't want to give the impression that Turkey has a weak local manufacturing sector or is a stranger to high tech industries.  Neither is true; they are actually capable of producing their own helicopter gas turbines, combat UAVs, missiles, and a variety of other quite challenging materiel.  Turkey has, current monetary woes aside, a well diversified and fairly well developed economy.  They're just not a match for South Korea, which has an extremely well-developed heavy industry and electronics sector relative to the country's size, natural resources and population.  Israel has an even smaller population and GDP, but their defense industry is outrageously well-developed for a country of that size for some mysterious reason, and there is abundant local expertise in the design of complex weaponry.

So, any country that is plausibly going to mass-produce a 1990s tech-level tank (and let's be honest, that's not dramatically different than a 2022 tech level tank) is going to need a fairly robust economy, well developed local heavy industry, and a large number of mechanical and electrical engineers.  I think the poorest of the countries I just listed is Romania, with the 39th largest GDP in the world (out of 190-something).  By the 1990s, being able to design and produce a tank on ones own was a privilege reserved for a fairly small number of countries.  Even countries that could plausibly design their own engine, transmission and tracks frequently farmed these out to Germany's Renk and Diehl, respectively.  Alternatively, you might say that Brazil in the 1980s represents the floor economy of a nation capable of designing and producing its own tank, although the entire turret on that vehicle is a British design from Vickers.

So that would be the first thing I would say about designing a 1990s tank; it's not for small nations, and even the rich ones frequently used foreign components.

As LoooSeR said, context is important.

During the 1940s, tanks were simple enough that relatively small countries could design and field reasonably competitive designs on their own.  The expertise required for tanks largely overlapped with either other armament industries (tank guns were often adapted naval, AA guns, or field artillery and the engines were often modified aircraft powerplants), or civilian heavy industries (much of the casting/welding and transmission design could be readily adapted from car/train/ship making industries).

By the 1990s, however, tanks were much higher tech and a lot of that tech was much more tank-specific.  It should be possible to adapt a helicopter turbine or heavy prime mover engine to work in a tank.  Fabrication of the hull could still probably be done with expertise from other industries.  Production of the special armor packages, transmission and running gear would require tank-specific knowledge but not necessarily tank-specific industry.  Production of the gun, fire control systems, and other combat electronics would by that point require very specific knowledge and would overlap relatively little with too many other things already in production if it were a nation's first tank.

I think it's instructive to look at the smallest/poorest countries that have produced their own tanks.  Romania was able to produce the TR-85, albeit in somewhat limited quantities, and they didn't design their own gun, and the turret and hull design are at least based on the design of the T-54/55 albeit very heavily modified.  As far as I can tell they did design their own engine and transmission, which is quite impressive, but this took some time and all the while they were cribbing notes off of foreign designs.  No shame in that; high specific output diesels are not easy to design.

Israel designed the Merkava, which has a completely original hull and turret design, locally designed suspension and tracks, and locally designed special armor packages and fire control on the later models.  The engine is either US or German designed, and the transmissions have been US, German or Israeli designed based on the mark.  The gun was a straightforward clone of the M68, and later a locally designed version of the German 120mm smoothbore.  Both of these guns are compatible with the wide range of ammunition in either caliber, although Israel has a local ammunition industry capable of designing and producing its own tank gun ammunition (which in some cases has been widely adopted outside of Israel).

South Korea has produced two MBTs locally, the K1 and K2.  The former had a great deal of assistance from Chrysler, but the latter appears to be a largely local effort.  Early K2s had a German designed engine and transmission, but these are eventually to be phased out and replaced with locally-designed equivalents.  I believe the tracks are German-designed.  Not sure about the suspension.  The armor packages and fire control system are locally designed and manufactured.  The gun is some sort of version of the German 120mm, although again South Korea is capable of designing and producing their own ammunition.

Turkey, which has roughly the same size economy as South Korea if we discount their current economic woes, has had a much harder time developing their own MBT.  Despite considerable help from South Korea, they have struggled to develop their own engine and transmission and are currently dependent on political good will from Germany if the project is to go forward quickly.  I don't want to give the impression that Turkey has a weak local manufacturing sector or is a stranger to high tech industries.  Neither is true; they are actually capable of producing their own helicopter gas turbines, combat UAVs, missiles, and a variety of other quite challenging materiel.  Turkey has, current monetary woes aside, a well diversified and fairly well developed economy.  They're just not a match for South Korea, which has an extremely well-developed heavy industry and electronics sector relative to the country's size, natural resources and population.  Israel has an even smaller population and GDP, but their defense industry is outrageously well-developed for a country of that size for some mysterious reason, and there is abundant local expertise in the design of complex weaponry.

So, any country that is plausibly going to mass-produce a 1990s tech-level tank (and let's be honest, that's not dramatically different than a 2022 tech level tank) is going to need a fairly robust economy, well developed local heavy industry, and a large number of mechanical and electrical engineers.  I think the poorest of the countries I just listed is Romania, with the 39th largest GDP in the world (out of 190-something).  By the 1990s, being able to design and produce a tank on ones own was a privilege reserved for a fairly small number of countries.  Even countries that could plausibly design their own engine, transmission and tracks frequently farmed these out to Germany's Renk and Diehl, respectively.  Alternatively, you might say that Brazil in the 1980s represents the floor economy of a nation capable of designing and producing its own tank, although the entire turret on that vehicle is a British design from Vickers.

So that would be the first thing I would say about designing a 1990s tank; it's not for small nations, and even the rich ones frequently used foreign components.

As for what a 1990s tank would realistically look like, by the 1990s most tanks were really samey.
 
Powerplant:  The earliest tanks with diesels were experimented with in the 1930s, I believe either the Japanese or the Soviets were the first.  By the 1940s the advantages were obvious, but de-rated aviation gasoline engines were reliable and already in mass production, so many countries stuck with those.  I'm less clear on the rationale for the Germans keeping gasoline motors as theirs were not aeroderivative.  In any case, there actually was a German tank diesel program, it just went nowhere.

By the 1990s there were pretty much two realistic possibilities for a tank powerplant; either a turbodiesel or a gas turbine.  1990s MBTs are about half armor by weight, so they're very sensitive to the compactness of things.  Turbocharged diesels don't have amazing power density, although with a lot of careful engineering they can be made competitive, but they have very low fuel consumption and lower waste heat rejection requirements than gasoline engines.  Once you factor in the volume of the engine plus the volume of the fuel plus the volume of the cooling fans, and the strategic mobility advantage the fuel-sipping diesel, it's definitely coming out ahead of the gasoline motor.

Gas turbines do not scale down particularly well.  Very large gas turbines like the 33,000 horsepower Rolls Royce WR-21 naval gas turbine in the Type 45 destroyer achieve 42% thermal efficiency, which is like middling efficiency by diesel standards.  A gas turbine that will fit inside of a tank is much less efficient; realistically about a match for a gasoline engine in terms of specific fuel consumption when it's at design point and much worse if it's idling or doing any kind of stop and go.  Gas turbines also need beefier air filters than diesels due to much higher mass airflow through the engine.  However, there are still a number of advantages that must be taken into consideration.  Gas turbines are (very nearly) completely self-cooling, so while there will still need to be cooling fans to keep the transmission cool, the total powerpack losses to cooling power will be smaller and the ballistic windows from the ventilation will be much smaller.  Gas turbines with a free power turbine (which is most of them) have a very different torque/RPM characteristics from a diesel; they produce max torque at their lowest RPM and max power at their minimum torque.  These are very favorable characteristics if you want to keep the transmission small (although the Abrams' XR-1100 transmission was, as I understand, designed to work with both the AVCR-1360 and AGT-1500 so it likely does not take much advantage of this effect).  Gas turbines are easier to start in the cold.  Gas turbines have very little vibration because their moving parts rotate rather than reciprocate.  Gas turbines are actually multi-fuel, no questions asked and no mucking around with adjusting the engine to suit the fuel.  The Brayton cycle uses continuous, constant-pressure ignition which simply does not care about octane numbers or cetane numbers.  Finally, it's easier to design gas turbine fuel burners so they produce very little smoke than it is to ensure that a diesel produces very little smoke due to the much different fuel burn stoichiometry of a gas turbine.  It should be noted that not all gas turbine designers have actually succeeded in doing so, however.

A gas turbine good enough for a tank would be roughly similar to a turboshaft for a helicopter, albeit tweaked more for better fuel consumption than for absolute power to weight ratio.  The list of countries that can design very good turboshaft engines is quite short, but then so is the list of countries that can make high specific power diesels.  If tank-sized gas turbines performed as well as ship-sized ones this would be no contest, but they don't so either choice is competitive and it's pretty ambiguous which is "best".  But most countries in the world realistically do not have the luxury to pick and choose between a top of the line diesel and a top of the line turbine.  Interestingly, the UK is in a position to make such a choice and they still managed to fuck it up somehow by fielding a tank diesel that's 300 horsepower short of its stablemates.  The French hyperbar engine is a turbocharged diesel, just tweaked for very fast throttle response and compactness at some expense to efficiency.

Armament:  By the 1990s, advances in digital fire control systems largely rendered gun-launched missiles obsolete.  There was probably still a case for them as a sort of long-range precision round for swatting at helicopters and the like, but that role could also be filled with something like M830A1.  There were various flirtations in the mid Cold War era with sorta-kinda howitzer like armament for tanks in the form of medium pressure guns and gun/launcher hybrids, but by the late 1970s there was basically a consensus amongst all sensible people that the tank armament of the future would either be the Rheinmetall 120mm or would look a lot like it.  Even British engineers were aware of this:



In any event, the Soviets taking their toys and going home meant that the world did not suddenly fill with various super-tanks, and tank lethality ended up being more economically improved by advances in ammunition design rather than arming the tanks with larger guns.



You can't go too much larger than current 120mm without requiring an autoloader.